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Vastly diluted bleach may have protective effect on skin

By Alyssa Botelho

When vastly diluted, bleach can have healing effects

(Image: George Doyle/Getty)

Forget Crème de la Mer, Crème de la bleach may be next on your bathroom shelf.

So suggests a discovery that highly diluted household bleach inhibits inflammation in the skin, a finding that might help protect skin from sun exposure, radiation therapy and even the natural ageing process.

Don’t try it at home, but doctors have known for decades that bathing in diluted bleach helps alleviate severe eczema. “But no one really knew why,” says Thomas Leung, a dermatologist at Stanford University in California. Many thought the antimicrobial properties of bleach kept the skin clean, and therefore less irritated.

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“But we weren’t fully convinced – the solution doctors use is so dilute that it isn’t fully antiseptic,” Leung says. The typical concentration used, just 0.005 per cent, is weaker than the amount you would find in swimming pool water.

Leung suspected that bleach might also be involved in stemming inflammation. An inflammatory response is vital for fighting infection but can cause damage when it spirals out of control – as it does in eczema.

Spa for mice

Leung’s team suspected a protein called NF-kB, which triggers the recruitment of inflammatory cells to a site of infection, might be involved. To test that hunch, they exposed human skin cells to a solution containing 0.005 per cent bleach for an hour.

The solution completely blocked NF-kB signalling. Hypochlorite – the active chemical in bleach – oxidizes, or plucks electrons off, a molecule that activates NF-kB and begins the inflammatory cascade. By putting that activator out of commission, hypochlorite can completely inhibit the inflammatory pathway.

Leung’s team next explored the therapeutic potential of the solution in mice with radiation dermatitis – a type of sunburn-like irritation often seen in people undergoing radiotherapy. They also tested the affect of bleach on healthy old mice with ageing skin.

Each group of mice was allowed to wade in a dilute bleach bath for 30 minutes a day. “We called it their spa treatment,” says Leung. Mice that took a bleach bath before each of their 10 daily radiation treatments had milder, faster-healing burns than those who took water baths.

That’s important, Leung says, because people with cancer often have to take time off from radiotherapy to let such burns heal before resuming treatment.

Once more unto the bleach

The old mice that took a bleach bath every day for two weeks had increased skin cell production resulting in thicker, younger-looking skin than old mice that took plain water baths. In addition, they had lower expression of two genes classically associated with ageing.

The effect was short lived, however. The rejuvenated skin returned to its elderly look after about two weeks because the action of bleach on Nf-kB is mild, and diminishes with time. It would have to be applied repeatedly to give anti-ageing effects, Leung says.

It is surprising that dilute hypochlorite is able to confer such protective effects on the skin, says Paul Robbins, who studies inflammatory and age-related diseases at the Scripps Research Institute in La Jolla, California. But given that hypochlorite is oxidative and so pulls electrons off other charged molecules, he adds, it could have many potential side effects, especially as dosage increases.

Leung says the fact that the action is reversible, and has not been shown to cause infection or other ill effects in his experiments, provides hope that side effects will be minimal in clinical trials.

“The novelty here is that we’re taking an incredibly cheap, widely available chemical and exploring additional applications,” Leung says. “Because we’ve been able to pinpoint hypochlorite’s precise mechanism of action in the body, now we can expand the use of a safe and widely used treatment even more.”